This paper introduces an empirical Wear Projection Technology (WPT) which relies solely on data from two (or more) time-independent wear related measurements at a wear site. The development and application of this WPT insures that it is completely general in nature. Thus, WPT is potentially useful for all wear experiences where measurements and related extrapolations and interpolations can be made before a “failure” occurs.
When applied to nuclear plant steam generator tubes using non-destructive examination measurements (obtained during in-service inspections) as input, WPT enables mechanism (typically turbulence and / or fluid-elastic induced vibration) independent and motion-type (sliding-only, impact-sliding or impacting) independent projections for each site with an ongoing wear process. A single application, or successive applications in a monitoring mode, provides the basis for proactive planning of inspections as well as for required decisions regarding the short and long term maintenance of that specific tube, of that specific steam generator, and finally, of that entire plant. Appropriate timing and number of applications provides plant operators with the basis to assure safe (and commercially optimum) continued operation under either constant or changing operating conditions.
This paper presents the development of WPT along with example results from steam generator tube straight-leg and U-bend applications. These applications include an input data error assessment and a qualification. Views on how WPT relates to the Proposed US-NRC Steam Generator Rule for the tube wear degradation mode, and how it can be used to implement an Alternate Plugging Criteria, are provided. Ideas relative to the implementation of the original wear process model and numerical methods to compute tube vibration and related wear are also presented.